This kind of absorbent article includes an absorber and a liquid pervious top sheet covering the front side of the absorber so that excrement liquids such as urine and menstrual blood pass through the top sheet and are absorbed and held by the absorber. Conventionally, as top sheets for absorbent articles, non-woven fabric fabricated by various methods, non-woven fabric perforated as secondary processing, porous films made from synthetic resins such as polyethylene, and others have been used. In many absorbent articles, to solve reflowing of excrement liquids from the top sheet to the skin, a second sheet formed from bulky non-woven fabric is stuck to the back surface of the top sheet.
The absorbent articles are required to prevent not only leakage of excretion such as urine but also the wearer's unpleasant feeling, rash, and the like caused by re-sticking of excretion such as urine to the skin. Accordingly, in recent years, in the case of using non-woven fabric for the top sheet, a large number of dome-shaped extruded projections is formed on the top sheet by embossing to decrease the area of contact between the top sheet and the skin, and the portions to be in contact with the skin are softened as described in Patent Documents 1 to 3. In particular, as described in Patent Document 3, when the peripheries of the extruded projections on the top sheet (the bottoms of recesses between the projections) and the second sheet are joined, the extruded projections are more firmly formed and securely maintained even in a pressed state in package bags until they are put to use through distribution process. Such the extruded projections preferably contribute to excellent absorbability and appearance. The embossed top sheet is not only highly functional but also offers beautility to the consumers, and is very important element in appearance as well.
These top sheet and second sheet can be joined at a three-roll processing facility illustrated in FIG. 12, for example. Specifically, the processing facility for the top sheet includes: a push roll 90 with a large number of push convex portions 90a arranged on the peripheral surface; a concave roll 91 that is opposed to the push roll 90, and has concave portions 91a corresponding to the push convex portions 90a and joint convex portions 91b provided between the concave portions 91a; and a joint roll 92 opposed to the concave roll 91. A top sheet material 30S is fed by drawing from the downstream side at a certain tension. The material is first sandwiched between the push roll 90 and the concave roll 91, and the convex portions on the push roll 90 enter into the concave portions 91a on the concave roll 91 to form a large number of extruded projections 31 (protrusions), and then is wound around the concave roll 91. While the material is guided by rotation of the concave roll 91, a second sheet material 40S is fed to the outside of the top sheet material 30S by drawing (extending) from the downstream side at a certain tension. The top sheet material 30S and the second sheet material 40S are sandwiched between the concave roll 91 and the joint roll 92, and are thermally pressed and attached between the joint convex portions 91b of the concave roll 91 and the outer peripheral surface of the joint roll 92, thereby forming top-second joint portions 80.
However, when the article described in Patent Document 3 is produced, a large number of wrinkles is formed along a MD direction (machine direction or sheet conveyance direction) of the top sheet processing facility with space left therebetween in a CD direction (direction orthogonal to the MD direction or transverse direction) as illustrated in FIG. 14(b), thereby leading to a problem of deterioration in appearance.